Method and apparatus for dual/multi-watch for group PTT services

ABSTRACT

A communication system ( 100 ) provides dual-watch and multi-watch capability for group PTT services. Incoming PTT calls are prioritized and played out in accordance with prioritized devices ( 130 ). A user of multiple communication devices can hear received audio traffic being played out in accordance with the priority assigned to the group call and the priority assigned to the communication device. Numerous calls can be simultaneously received and managed.

FIELD OF THE INVENTION

The invention generally relates to communication systems and moreparticularly to managing calls across multiple push-to-talk (PTT)devices.

BACKGROUND OF THE INVENTION

Push-to-talk (PTT) is a two-way communication service that operates likea “walkie talkie.” PTT is half-duplex, meaning communication can onlytravel in one direction at any given moment. By contrast, a typical cellphone, call is full-duplex, meaning both parties can hear each other atthe same time. There also exists communication devices that provide bothfull-duplex and half-duplex capabilities. PTT requires the personspeaking to press a button on the communication device while talking andthen release it when they are done. The listener then presses a PTTbutton on their own communication device to respond. Most PTT systemsallow group calling, meaning one person can speak to everyone in theirassigned or current group at once, just by pressing a PTT key. Some PITsystems use voice-over-IP (VoIP) technology to provide PTT servicedigitally over digital data networks. Public safety personnel, such aspolice officers, firefighters and rescue workers to name a few, utilizea variety of different communication devices in the field, includingportable handheld radios, cell phones, mobile (vehicular) radios andaccessories.

Public safety personnel often desire to listen to multiple PTT groups atone time. Typical solutions managing multiple PTT groups includescanning the groups listed in a scan list by various methods, thenplaying the audio when traffic is detected. Priorities are usually usedin the scan list. Conventional scanning typically involves tuning todifferent radio frequency (RF) frequencies one by one and staying tunedto a frequency when activity is detected. Trunked scanning typicallyinvolves having an infrastructure entity report which groups haveactivity, with enough information to allow the radio to listen in ondesired groups by tuning to a channel. However, both conventionalscanning and trunked scanning are prone to missed calls, particularlywhen there is audio activity on two or more groups.

Accordingly, it would be desirable to improve call management incommunication systems that utilize numerous communication devices.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying figures where like reference numerals refer toidentical or functionally similar elements throughout the separate viewsand which together with the detailed description below are incorporatedin and form part of the specification, serve to further illustratevarious embodiments and to explain various principles and advantages allin accordance with the present invention.

FIG. 1 is a block diagram of a communication system having multipledevices operating in accordance with various embodiments of theinvention.

FIG. 2 is a flowchart of a method for managing multiple calls frommultiple devices within a communication system in accordance withvarious embodiments of the invention.

Skilled artisans will appreciate that elements in the figures areillustrated for simplicity and clarity and have not necessarily beendrawn to scale. For example, the dimensions of some of the elements inthe figures may be exaggerated relative to other elements to help toimprove understanding of embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Before describing in detail embodiments that are in accordance with thepresent invention, it should be observed that the embodiments resideprimarily in apparatus components and methods related to managingmultiple calls across multiple devices via the use of dual watch ormulti-watch.

Accordingly, the apparatus components have been represented whereappropriate by conventional symbols in the drawings, showing only thosespecific details that are pertinent to understanding the embodiments ofthe present invention so as not to obscure the disclosure with detailsthat will be readily apparent to those of ordinary skill in the arthaving the benefit of the description herein.

In this document, relational terms such as first and second, top andbottom, and the like may be used solely to distinguish one entity oraction from another entity or action without necessarily requiring orimplying any actual such relationship or order between such entities oractions. The terms “comprises,” “comprising,” or any other variationthereof, are intended to cover a non-exclusive inclusion, such that aprocess, method, article, or apparatus that comprises a list of elementsdoes not include only those elements but may include other elements notexpressly listed or inherent to such process, method, article, orapparatus. An element proceeded by “comprises . . . a” does not, withoutmore constraints, preclude the existence of additional identicalelements in the process, method, article, or apparatus that comprisesthe element.

In the description herein, numerous specific examples are given toprovide a thorough understanding of various embodiments of theinvention. The examples are included for illustrative purpose only andare not intended to be exhaustive or to limit the invention in any way.It should be noted that various equivalent modifications are possiblewithin the spirit and scope of the present invention. One skilled in therelevant art will recognize, however, that an embodiment of theinvention can be practiced with or without the apparatuses, systems,assemblies, methods, components mentioned in the description.

The call management technique and apparatus to be described herein isaccomplished using dual watch or multi watch. Dual-watch is the abilityto simultaneously listen to audio activity in two groups. Multi-watch isthe ability to listen to two or more groups simultaneously. Dual-watchis accomplished by some public safety users by tuning multiple radios todifferent groups. These users are accustomed to listening tosimultaneous call streams, typically occurring with a mobile(vehicle-based) radio and a portable (handheld) radio. It should benoted that although it is counter-intuitive, public safety users areaccustomed to processing simultaneous audio streams and tuning into adesired audio stream, even in the presence of many other competing audiosources, including multiple radio transmissions. While prior approachesto dual watch have focused on multiple transceivers for call terminationat a single device, the ability to manage multiple calls from multipledevices, such as calls coming in over different public safetybroadcasts, would be highly beneficial. Briefly, in accordance withvarious embodiments of the invention to be described herein, a methodand apparatus provide dual/multi-watch across multiple devices alongwith intelligent call management. Additionally, the use of a VoIP pathfor dual/multi-watch is provided.

Users working in the public safety environment commonly carry both acellular phone and a two-way radio, which for the purposes of thisapplication will be referred to as a phone and a radio, respectively.There are phones that support PTT calls and some that support group PTTcalls over a cellular network. The PTT service is typically handled overan internet protocol (IP) stream, such as the Open Mobile Alliancepush-to-talk over cellular (OMA PoC) standard. Such a service uses asoftware application that, for the purposes of this application, willreferred to as a PTT-VoIP client.

The call management configuration operating in accordance with thevarious embodiments of the invention provides a way of accomplishingdual watch by receiving simultaneously on a radio and a phone. Theconfiguration has an added feature of being able to receive more thantwo audio streams on the phone thereby enabling multi-watch. Referringto FIG. 1 there is shown a communication system 100, such as a publicsafety network, operating in accordance with the various embodiments ofthe invention. Communication system 100 includes a plurality ofcommunication devices 130 under the control of a user. The plurality ofcommunication devices and accessories 130 includes a radio 102, a phone104, a mobile (in-vehicle) radio 106, an earpiece 108 and a remotespeaker microphone (RSM) 110. The radio 102, the phone 104, the mobileradio 106, the audio earpiece 108, and the RSM 110 have speakersproviding audio sinks over which the user hears audio. The speaker ofradio 102 is a loud speaker and for the purposes of this applicationprovides a preferred location for porting audio of a higher prioritygroup, or porting a call a user is more actively involved in. Thedevices in 130 may be operably coupled over a personal area network(PAN) or other coupling means. Additional devices or fewer devices mayalso be used, but those shown illustrate a realistic example of thenumerous devices a public safety officer may need to manage at any giventime. A PTT-VoIP application resides in at least one of the devices tosupport PTT calls over an alternate network 118.

Communication system 100 is linked via a gateway component 114 whichperforms an application-layer conversion of information from oneprotocol stack to another, such as land mobile radio (LMR) network 112to the alternate network 118 (and vice versa). The gateway component 114includes LMR gateways. LMR gateways provide voice interoperabilitybetween radio and non-radio networks by bridging radio frequencies to IPstreams, such as produced by alternate network 118. Examples of LMRnetworks are those that adhere to the APCO Project 25 standard and theTetra standard. Examples of alternate networks are CDMA EVDO and GSMHSDPA cellular data/voice networks.

In accordance with various embodiments, the dual/multi-watch is managedwith a coordinated approach between the devices 102, 104, 106, 108, and110. The coordination can be implemented by a single PTT VoIP client inthe radio 102 or phone 104 or mobile radio 106, or by multiple PTT VoIPclients in communication over a PAN. Regardless of the VoIP clientlocation, the features of the call management operate as follows. Theuser of the plurality of devices 130 has a single list of groups theyare interested in listening to, with preference rules describing thetype of operation desired for each group. The list may haveprioritization. The prioritization can be the traditional allocation ofa first priority group, a second priority group, and the rest normalpriority, or any other form of prioritizing between the groups the userwishes to configure. The prioritization may also be based on the type ofincoming PTT call is being received, such as emergency given highestpriority while non-emergency calls would be assigned lower priority.Another preference stored within the list may be the designation of apreferred audio device, which denotes which device is preferred for thehighest priority audio. In most public safety applications, the highestpriority audio would likely be defaulted to the radio 102. The selecteddefault is based on historical data that has shown that users who carrya radio are most likely to have that device on their person than anyother, and prefer PTT audio through that device. However, as userapplications may vary, different devices could be selected as thedefault, or assigned different priorities, if desired.

In one embodiment, the highest priority active call traffic is playedthrough the preferred audio device, and the next highest priority callaudio is played through another device. As traffic starts and stops,audio may move to the second device if a higher priority group hasactivity, or the system may let that current transmission play outbefore moving subsequent transmissions to the second device since PTTtransmissions tend to be very short (3-5 seconds). So for the case ofthe highest priority audio being assigned to the radio 102, two incomingcalls would result in the highest priority call playing out the radio102 and the next highest priority call playing out the phone 104. Athird and fourth call coming in to the user of devices 130 could beplayed out at mobile radio 106 or earpiece 108, RMS 110 or otherprioritized audio sinks.

The call management technique in accordance with various embodiments canalso address mobility within the system. A distributed mobility approachis defined to choose between narrowband (NB) path between 112 and 114,and VoIP path between 114 and 118 for monitoring a group. The callmanagement expands to allow for dual/multi-watch considerations, wherebya specific group can be monitored using the NB radio 102, and the othergroups can be monitored via the VoIP path. It is likely, but notnecessary, that the highest priority group would be the one assigned tothe NB radio 102.

Among the considerations for where to place the PTT VoIP client,choosing to have the PTT VoIP client in the radio 102 and not in thephone 104 allows the radio 102 to use an off-the-shelf phone 104 using astandard modem profile from a PAN technology such as Bluetooth.

An alternative embodiment is to have the PTT VoIP client in the phone104 and have the phone 104 forward audio over the PAN to the radio 102thereby handling the call processing in the phone.

Additionally in yet another embodiment, the PTT VoIP client can exist inboth the phone 104 and the radio 102. This embodiment allows redundancybecause PTT-VoIP calls can be handled in either device.

Another aspect to the various embodiments of call management is thehandling redundancy. If the devices loose PAN connectivity, or by manualsetting or other means it is determined that the user wants to restrictoperation to a single device, dual/multi-watch can be restricted to thatdevice, to the degree that the single device is capable. If this singledevice mode happens and PAN connectivity is still there, the otherdevice can still be used purely as a modem.

The call management technique operating within a communication systemprovides the advantage of spatial separation between audio sinks makingmultiple audio streams easier to understand. The call managementtechnique is further advantageous in a mobile (vehicle) configurationwhere there is further spatial separation between the audio sinks Inaddition to having spatial separation between audio sinks the callmanagement technique may sum two or more call audio streams to a singleaudio sink when based on assigned device priority and call priority.

Referring to FIG. 2, the call management technique 200 in accordancewith various embodiments is shown. Step 202 begins by detecting audioactivity on a channel (for example C1) from a scan list. As mentionedbefore the scan list is pre-stored and the types of incoming calls andgroups are prioritized. A check is made at 204 to determine if theprimary device is playing audio, if not then the audio traffic onchannel C1 is played on the primary device at 206. If a determination ismade at 204 that audio is being played on the primary device, then adetermination is made at 205 as to which channel the audio originatesfrom and then a priority check is made at 208. If channel C1 does nothave a higher priority than channel C2 at 208, then a determination ismade at 210 as to whether the secondary device is playing audio at 210.If the secondary device is playing audio at 210, then audio traffic fromchannel C1 goes to the secondary device at 214. If audio is alreadybeing played on the secondary device at 210, then the C1 audio is summedto the audio on the secondary device at 212.

If channel C1 does have higher priority than channel C2 back at 208,then a check is made to determine if audio is playing on the secondarydevice at 216. If the secondary device is not playing audio at 216, thenchannel C1 audio is played on the primary device and channel C2 audio ismoved over to the secondary device at 220. If audio is played on thesecondary device at 216, then channel C1 audio plays on the primarydevice, and the C2 audio is moved over to be summed with the currentaudio playing on the secondary device at 218. While described in termsof two devices, technique 200 is expandable to encompass as manyprioritized devices as are in the communication system 100. Technique200 may also vary based on device audio preferences, audio summingpreferences, and allocation of a given group or priority to a device, aspreviously described.

In the embodiment just described the channels are assigned thepriorities for scan. However, in an alternative embodiment the callpriority can be based on the type of incoming PTT being received. Forexample, in APCO systems the calls have only one of two priorities(emergency or not), but in Tetra and OMA PoC systems, the calls have anumeric priority. The comparisons steps associated with flowchart 200can be based on the priority of the type of call and be played outaccording to the prioritized devices. So for example, if preferred groupcall is played out over radio 102 while another group call is beingplayed out over phone 104, and an emergency call comes in, then theemergency call, having the highest priority, would bump, the preferredgroup call over to the phone and the other group call would be bumpedover to the mobile radio 106 or the earpiece 108 or the RSM 110depending on how the devices were prioritized. Calls can also be summedto play out of the same device at different times as has also beendescribed.

Accordingly, there has been provided a method and apparatus for managingcalls across multiple devices. The call management technique isbeneficial to government and public safety type operations wheremultiple calls may be coming in to a listener of multiple devices at thesame time. Unlike the prior approaches to dual watch which have focusedon multiple transceivers/speakers, each dedicated to a channel or group.The call management operating in accordance with the various embodimentsprovides dual/multi watch across multiple devices and manages themintelligently resulting in fewer missed calls, improved audiointelligibility, and device redundancy. The call management techniquecan also be readily adapted as different applications relating topriority arise.

Those skilled in the art will appreciate that the above recognizedadvantages and other advantages described herein are merely exemplaryand are not meant to be a complete rendering of all of the advantages ofthe various embodiments of the present invention.

In the foregoing specification, specific embodiments of the presentinvention have been described. However, one of ordinary skill in the artappreciates that various modifications and changes can be made withoutdeparting from the scope of the present invention as set forth in theclaims below. Accordingly, the specification and figures are to beregarded in an illustrative rather than a restrictive sense, and allsuch modifications are intended to be included within the scope of thepresent invention. The benefits, advantages, solutions to problems, andany element(s) that may cause any benefit, advantage, or solution tooccur or become more pronounced are not to be construed as a critical,required, or essential features or elements of any or all the claims.The present invention is defined solely by the appended claims includingany amendments made during the pendency of this application and allequivalents of those claims as issued.

What is claimed is:
 1. A method of managing incoming calls in acommunication system, comprising: assigning device priority to aplurality of communication devices under the control of a single user,each communication device having a speaker; assigning call priority forPush-to Talk (PTT) calls expected by the user; storing the assigneddevice priority and assigned call priority to a scan list; scanning thescan list; receiving a plurality of incoming PTT calls in response toscanning, wherein the plurality of incoming PTT calls are associatedwith different group calls; and coordinating a concurrent playing out ofthe plurality of incoming PTT calls over two or more devices of theplurality of communication devices based on the assigned device priorityand the assigned call priority thereby providing multi-watch over thereceived incoming calls.
 2. The method of claim 1, wherein the step ofplaying the plurality of incoming PTT calls comprises: moving audiotraffic from one device to another device of the plurality of deviceswhen a higher priority PTT call is received.
 3. The method of claim 1,wherein playing the plurality of incoming PTT calls comprises: summingaudio traffic from two different PTT sources; and playing the summedaudio traffic at different times on the same communication device. 4.The method of claim 1, wherein the step of receiving comprises:determining whether a first priority device from amongst the pluralityof communication devices is currently playing audio traffic; comparingchannel priority of the incoming PTT call to the channel of thecurrently playing audio traffic in response to determining that audiotraffic is currently being played; and adjusting a location to play-outthe incoming PTT call and the currently playing audio traffic based onthe step of comparison.
 5. The method of claim 1, the step of receivingcomprises: determining whether a first priority device from amongst theplurality of communication devices is currently playing audio traffic;comparing the type of incoming PTT call to the type of currently playingaudio traffic in response to determining that audio traffic is currentlybeing played; and adjusting a location to play-out the incoming PTT calland the currently playing audio traffic based on the step of comparison.6. The method of claim 1, wherein the step of receiving furthercomprises receiving the incoming PTT calls at one or more of theplurality of communication devices; and linking the plurality ofcommunication devices over a land mobile radio (LMR) gateway andalternate Voice over Internet Protocol gateway for radio to non-radiocommunication.
 7. A communication system for managing incoming calls,the communication system comprising: a plurality of user communicationdevices, each user communication device having a speaker; a Push-to Talk(PTT) client that is implemented in one or more of the plurality of usercommunication devices and that is configured to: assign a devicepriority to each of the plurality of user communication devices; assigncall priority for PTT calls expected by a user of the plurality of usercommunication devices; store the assigned device priority and assignedcall priority to a scan list; scan the scan list; receive a plurality ofincoming PTT calls in response to the scanning, wherein the plurality ofincoming PTT calls are associated with different group calls; andcoordinate a concurrent playing out of the plurality of incoming PTTcalls over the plurality of user communication devices based on theassigned device priority and the assigned call priority, therebyproviding multi-watch over the received incoming calls.
 8. Thecommunication system of claim 7, wherein the PTT client is configured toplay the plurality of incoming PTT calls by moving audio traffic fromone user communication device to another user communication device ofthe plurality of user communication devices when a higher priority PTTcall is received.
 9. The communication system of claim 7, wherein thePTT client is configured to play the plurality of incoming PTT calls by:summing audio traffic from two different PTT sources; and playing thesummed audio traffic at different times on the same user communicationdevice.
 10. The communication system of claim 7, wherein the PTT clientis configured to receive a plurality of incoming PTT calls by:determining whether a first priority user communication device fromamongst the plurality of user communication devices is currently playingaudio traffic; comparing channel priority of the incoming PTT call tothe channel of the currently playing audio traffic in response todetermining that audio traffic is currently being played; and adjustinga location to play-out the incoming PTT call and the currently playingaudio traffic based on the step of comparison.
 11. The communicationsystem of claim 7, wherein the PTT client is configured to receive aplurality of incoming PTT calls by: determining whether a first priorityuser communication device from amongst the plurality of usercommunication devices is currently playing audio traffic; comparing thetype of incoming PTT call to the type of currently playing audio trafficin response to determining that audio traffic is currently being played;and adjusting a location to play-out the incoming PTT call and thecurrently playing audio traffic based on the step of comparison.
 12. Thecommunication system of claim 7, wherein the PTT client is configured toreceive a plurality of incoming PTT calls by: receiving the incoming PTTcalls at one or more of the plurality of user communication devices; andlinking the plurality of user communication devices over a land mobileradio (LMR) gateway and alternate Voice over Internet Protocol gatewayfor radio to non-radio communication.